Support is requested for a Keystone Symposia meeting entitled Stromal Cells in Immunity, organized by Shannon J. Turley, Burkhard Ludewig and Melody A. Swartz. The meeting will be held in Keystone, Colorado from February 7-11, 2016. Stromal cells play instrumental roles in coordinating innate and adaptive immune responses. In healthy individuals, stromal cells and their determinants promote lymphoid tissue development, immune homeostasis, vascular function, host defense, and wound healing. Emerging evidence indicates that stroma can also contribute to immune-related disorders, including inflammatory and autoimmune diseases, allergy, asthma, fibrosis, edema, infection and vaccination; however, more research is needed to bolster this important and emerging field. More specifically, stromal cell function in HIV infection is significantly altered, leading to pronounced fibrosis in secondary lymphoid organs throughout the body. These fibrotic lesions prevent T cells from accessing critical growth factors that ensure lymphocyte survival and immune reconstitution in patients on anti-retroviral therapy. Recent studies also suggest that fibrotic reactions in lymphoid tissues may impair proper responses to vaccines; thus, additional research, collaboration, and education are critically needed to better understand stromal cell interactions with the immune system and how targeting the stromal compartment can improve human health.